Functional micro-ultrasound imaging of rodent cerebral hemodynamics

Quantification of blood flow and volume in arterioles and venules of the rat cerebral cortex using functional micro-ultrasound

“…Male Sprague-Dawley rats (Charles River Laboratories Inc., Saint-Constant, Quebec, Canada) (N = 13) were anesthetized with isoflurane, tracheotomized, mechanically ventilated and placed on a heating pad as described in Lindvere et al (2010) and van Raaij et al (2011). The femoral artery, femoral vein and tail vein were cannulated for blood gas sampling/blood pressure monitoring, delivery of α-chloralose during imaging, and delivery of ultrasound contrast agent respectively.…”

“…Functional micro-ultrasound imaging (fMUS, (van Raaij et al, 2011)) is a recent adaptation of high-frequency ultrasound imaging (Foster et al, 2002) that allows quantitative measurement of changes in CBV and CBF. The contrast mechanism used to measure hemodynamic parameters may be either power Doppler imaging of moving red blood cells (Mace et al, 2011) or nonlinear imaging of microbubble contrast agents (van Raaij et al, 2011).…”

“…The contrast mechanism used to measure hemodynamic parameters may be either power Doppler imaging of moving red blood cells (Mace et al, 2011) or nonlinear imaging of microbubble contrast agents (van Raaij et al, 2011). The term 'functional' is used here in the wider sense of measuring hemodynamic parameters of a steady-state situation, though it can also be used in a narrower definition as referring to a hemodynamic response to a stimulus.…”

“…(The perfluorocarbon gas that is released upon disruption as shell-less bubbles circulates briefly and freely through the vasculature, eventually dissolves in the plasma, and is released by the lungs.) We use a commercially available micro-ultrasound system to image these parameters with 100 μm spatial and 40 ms temporal resolution (van Raaij et al, 2011). Additionally, we investigate hemodynamic differences in cortical arterioles and venules using color Doppler imaging, which detects whether flow is towards or away from the ultrasound transducer.…”

Ultrafast Doppler for neonatal brain imaging

“…However its use for brain functional imaging remains poorly sensitive (van Raaij et al, 2011). Various types of bubbles have been developed for imaging purpose or drug and gene delivery (Leinenga, et al, 2016).…”